bkmagby

I was hoping that someone could explain how the header heat shield works? It appears to be only a barrier between the header and the right side of the engine compartment. So how can it reduce engine compartment heat? It is not sealed off from the rest of the engine compartment. It is open on top, and in front, so how can it reduce under hood heat? I'm not saying that it doesn't, I would just like someone to explain to me how it could? It seams more like it is there to be an immediate barrier to anything that may touch the header, or simply be to close over a long period of time. But as far as reducing the overall under hood heat, I don

xviper

It blocks much of the radiant heat from the header. Granted, there will be convected heat but as long as the car is moving through the air, there is constant flow through the engine bay. If the car just sat and idled, the engine bay temps would get very hot from convected heat.
Ever sit close to a fireplace? Notice any difference between having the mesh screen open vs closed? And the mesh is full of holes (open) but it's a lot cooler with the screen drawn.

bkmagby

I suppose your explanation makes since, but the key word you used is "radiant heat" and that is just what it will do. So since the header heat shield is open at the top, front and bottom, the heat will still radiate out from the header while the car is setting still or moving slow. It will rise up and over the heat shield and forward, which seems like it would direct allot more heat right at the air box during stop and go traffic when heat soak is most experienced. Also, if it does hold more heat inside of the heat shield, it is holding it right up next to the engine itself, and I can

xviper

Stop and go traffic "heat soak" is a well posted issue on this forum. It's not new.
I have a Toda header in which the heat shield has been eliminated. I found the underhood temps became so high and obtrusive, that I got a vented hood. Don't underestimate what that header heatshield can do. Radiated heat can be far more intense that convected heat.

I'm not sure what you are striving for. Are you trying to find some justification for removing it?

bkmagby

Just looking at some of the headers like Comptech that do not provide for putting the heat shield back on. Comptech says that it is not needed. But Honda put it on, so I am trying to establish it's exact function so I can make a decision as to weather I believe Comptech and decide to go ahead and buy their header, or look elsewhere. I don't want to do anything to hurt my car, or reduce its performance. I have seen a lot of cars with headers, and none of them have ever had a heat shield like this before. Thanks.

xviper

Due to the close proximity of things in the engine bay, I believe Honda put these shields in to protect things like the battery on LHD cars and the brake and clutch reservoirs on RHD cars from boiling their fluids. Things on an S2000 can't always be compared to other vehicles.
People have been putting on Comptech, Toda, and all sorts of headers for years without getting too worked up over the lack of heat shields. You're over-thinking this thing way more than the subject deserves.
If you are that concerned about it, there are mainly two aftermarket headers that will retain the heatshields - Rick's and Mugen.
BTW, none of them will give you enormous power gains.

WyattH

Isn't the shield also there because hotter gasses move faster?

xviper

I doubt the presence or absence of that header heatshield will contribute to any significant differences in exhaust gas temps.

bkmagby

That is a big problem I have

xviper

You're not alone. Forums like this tends to concentrate people who spend a lot of time working brain cells on all sorts of little things. You've come to the right place.